Ford F-150 1999 Workshop Manual page 8

1999 F-150/250 Workshop Manual
A/C Damper Door Switch Supply Hose
A12 LEAK TEST THE JUMPER VACUUM HARNESS
A13 REVIEW THE VEHICLE'S HISTORY
A14 CHECK THE VACUUM HOSES TO DAMPER DOORS
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Connect a vacuum pump to the supply hose and try to apply vacuum. If the vacuum pump can pull vacuum, the
hose is plugged. If the vacuum pump pulls partial vacuum, the hose is restricted.
Is the hose plugged or restricted?
Yes
REPLACE the supply hose. TEST the system for normal operation.
No
RECONNECT the A/C damper door switch supply hose. GO to
Disconnect the suspect hose.
Plug one end of the suspect hose and attach a vacuum pump to the other end. Apply 51 kPa (15 in-Hg) of
vacuum to the hose.
Does the vacuum drop?
Yes
REPAIR or REPLACE the vacuum jumper harness. TEST the system for normal operation.
No
REPAIR or REPLACE the function selector switch. TEST the system for normal operation.
Review the vehicle's history.
Did the climate control system function properly prior to this concern?
Yes
GO to A16.
No
GO to A14.
Connect a vacuum pump to each hose and try to pull a vacuum. If the vacuum pump can pull a vacuum, the hose
is plugged. If the vacuum pump pulls a partial vacuum, the hose is restricted.
Is a hose plugged or restricted?
Yes
REPLACE the vacuum hose. TEST the system for normal operation.
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8/16/2010